Malaria (vector: Anopheles gambiae) is a major infectious disease that kills about 1 million people each year. For the improvement of its treatment and vector control during the past decades, several issues such as high medicine cost, insecticide resistance, and lack of an effective vaccine have prevented adequate control of malaria. Additionally, the low selectivity of malaria vector insecticides also presents a public health problem. The purpose of developing novel carbamate insecticides in our laboratory is to offer effective and selective insecticide options to achieve the ultimate goal of malaria control.First, 50% inhibition concentration (IC 50 ) data was collected from three mammalian AChEs with eight commercial carbamate insecticides by using the Ellman assay. The IC 50 values varied from 57 nM to 7358 nM. The AChE sensitivity pattern and level were shown to be similar between the recombinant mouse and ICR male mouse brain cortex homogenate (slope = 0.99, R 2 = 0.96).Then eight novel carbamate insecticides that are possible malaria vector control agents were selected for further neurotoxicity testing in non-target organisms. Neurotoxic esterase (NTE) assay showed that the novel carbamates did not significantly inhibit NTE, inhibition of which underlies a significant hazard for anticholinesterases, especially organophosphates, in several nontarget vertebrate organisms. The NTE activity in the presence of novel carbamate insecticides ranged from 93% to 116% of the control, while in the commercial group, bendiocarb significantly inhibited NTE, leaving only 76.5% of the initial reactivity at 1 mM inhibitor concentration.Further in vivo bioassay using Daphnia magna was conducted to compare the aquatic toxicity of commercial and novel carbamates. The data showed that except for PRC331 (3-tertbutylphenylmethylcarbamate), all novel carbamates were of similar potency as bendiocarb (LC 50 = 611 nM) for aquatic toxicity, and their LC 50 values ranged from 172 nM (PRC331) to 1109 nM.In conclusion, the novel carbamate insecticides would appear to be an improvement over commercial carbamate insecticides because of greater selectivity, negligible NTE inhibition capacity, but in some cases with potent in vivo toxicity to Daphnia magna. However, since the envisioned usage of these compounds is in bednets or as indoor residual sprays (IRS), any environmental exposures to nontarget aquatic organisms are expected to be minimal.iv ACKNOWLEDGEMENTS